The crew of the CL-600 received a false localizer course capture when they selected the approach mode on their flight management system. False localizer course capture is a known problem, for which AIP has an established procedural defence at COM3.13.1. When the crew selected approach mode, the aircraft was well outside the parameters that are recommended by AIP COM3.13.1 and near (or beyond) the limit at which the integrity of the ILS is verified. The recent recurrences of false localizer course captures may indicate a requirement to remind pilots of the guidance provided in AIP. This requirement may be even more compelling in the case of foreign air carriers that operate in Canada, because these carriers may not have easy access to AIP.Analysis The crew of the CL-600 received a false localizer course capture when they selected the approach mode on their flight management system. False localizer course capture is a known problem, for which AIP has an established procedural defence at COM3.13.1. When the crew selected approach mode, the aircraft was well outside the parameters that are recommended by AIP COM3.13.1 and near (or beyond) the limit at which the integrity of the ILS is verified. The recent recurrences of false localizer course captures may indicate a requirement to remind pilots of the guidance provided in AIP. This requirement may be even more compelling in the case of foreign air carriers that operate in Canada, because these carriers may not have easy access to AIP. When the crew selected approach mode, the aircraft was inside the recommended distance from the airfield but near or beyond the limits at which the integrity of the ILS is verified.Findings as to Causes and Contributing Factors When the crew selected approach mode, the aircraft was inside the recommended distance from the airfield but near or beyond the limits at which the integrity of the ILS is verified. Some ground and airborne ILS equipment are known to be incompatible. This incompatibility may occasionally cause false or incorrect localizer course captures. Recent recurrences of false localizer course captures may indicate a requirement to remind pilots of the guidance provided in AIP.Findings as Risk Some ground and airborne ILS equipment are known to be incompatible. This incompatibility may occasionally cause false or incorrect localizer course captures. Recent recurrences of false localizer course captures may indicate a requirement to remind pilots of the guidance provided in AIP. AIP COM 3.13.1 outlines an established procedural defence that, if used, will reduce the risk of false or incorrect localizer captures.Other Findings AIP COM 3.13.1 outlines an established procedural defence that, if used, will reduce the risk of false or incorrect localizer captures. TSB Pacific Region forwarded a copy of Transport Canada's 29April 1993 aviation notice to the operators involved in this occurrence. These operators then provided copies to all of their pilots.Safety Action Taken TSB Pacific Region forwarded a copy of Transport Canada's 29April 1993 aviation notice to the operators involved in this occurrence. These operators then provided copies to all of their pilots.